This project is designed to examine in vivo and in vitro the role of cyclic AMP in modulating the secretion of ions, water, mucous, glycoproteins, and inflammatory mediators from specific cell types within the dog, cat, and ferret trachea. Using immunocytochemical techniques I will correlate changes in intracellular cyclic AMP in airway secretory cells in response to stimulation by neural, pharmacologic, or irritant agents with physiologic responses in these cells. I will combine physiologic, immunopharmacologic, and anatomic methods to study: the speciic cellular and subcellular localization of cyclic AMP in dog, cat, and ferret trachea; the relationship between cyclic AMP levels demonstrated immunocytochemically within specific cell types and cyclic nucleotide concentrations measured chemically in whole tissue; the effect of humoral versus neural stimulation of parasympathetic and sympathetic pathways, metabolites of arachidonic acid, and bacterial toxins on cyclic AMP levels measured immunocytochemically and by protein binding, and the relationship to transport and secretion. As part of the multidisciplinary study of neurohumoral regulation of lungs and airways at the Cardiovascular Research Institute, this project will focus on the nervous and humoral mechanisms which modulate cellular function in the trachea. I will use immunocytochemical and biochemical methods to evaluate the role of cyclic AMP in initiating and modulating secretory responses in specific cell types; morphologic methods to examine these cell types and their response to stimulation; and physiological, pharmacological, and biochemical methods to study the transport and secretion of ions, glycoproteins, and mediators from these cells. Results from these studies will provide insights into the mechanisms which mediate airway responses to a variety of stimuli. The immunocytochemical probe for cyclic AMP will provide information on receptor modulation of individual cells which is not available from chemical assays of cyclic AMP or chemical measurement of receptors in these tissues. This information will add to our understanding of diseases such as asthma, chronic bronchitis, and cystic fibrosis, in which abnormalities in secretion play a major role.